The field of the invention relates generally to video cameras, and more specifically to video camera systems which may store operating parameter information, and which may collect information reflecting uses of the system. The camera system may then use the information to operate at optimum conditions, to provide a performance history or for other reasons.
In the recent past, the need for small, lightweight video cameras using a solid state image sensor such as a charge coupled device ("CCD"), charge injection device ("CID") or metal oxide semiconductor ("MOS") has rapidly developed for both medical and industrial applications. One medical application involves a CCD which is attached to an endoscope to observe a surgical site. In this arrangement, the CCD may be contained in a small camera head and attached to the endoscope eyepiece so that the camera head/endoscope combination, or video-endoscope, is lightweight and easily manipulable by a surgeon. A flexible cable connects the camera head to the rest of the camera electronics which are usually included in a camera control unit located at a remote location. The camera control unit includes control and video processing circuitry which send operating signals to the CCD and receive signals from the CCD which are processed for video display. The camera control unit is also coupled to a video monitor for viewing of the surgical site by one or more physicians.
An industrial application employing a CCD involves observation of industrial processes where direct observation by a person is unsafe or otherwise impractical. Such processes include those occurring in nuclear power generating stations, furnaces or engine compartments, or other processes which are generally inaccessible. Here, a camera head including a CCD may be attached to a hole in the wall of the vessel in which the process occurs. The camera head is then connected by cable to a camera control unit and video monitor at a remote location in similar fashion described above.
The type of CCD or other solid state image sensor used for various medical or industrial applications may differ. However, all solid state imagers are not exactly alike, and to achieve peak or even acceptable performance, each solid state imager must be operated by the camera control unit at the imager's particular operating parameters. For example, different CCDs operate at varying substrate voltages and if the control unit supplies too much voltage to the CCD, the resulting video display exhibits noise and interference. Essentially, each CCD or other imager has its own personality that should be known to the camera control unit for the CCD to produce an optimum video picture signal. While it may be possible to provide different control units to accommodate the varying operating parameters of various imagers, such an arrangement is expensive and generally impractical. Thus an existing problem is poor interchangeability of imagers with camera control units or the sacrifice of optimum imager operating conditions and video display. This problem is significant because for example, different CCDs are typically used in connection with the same camera control unit.
For example, during a surgical procedure a problem may arise with the camera head requiring its, and the CCD's replacement. Also, video-endoscopes where the camera head is permanently attached to the endoscope are now used but a surgical procedure may require more than one type of endoscope and thus more than one CCD. To avoid changing the control unit, and to avoid sacrificing video quality, time-consuming adjustments to the control unit to vary the signals it sends to operate the CCD are necessary. However, because the control unit is typically located outside the arbitrary sterile area surrounding the patient, an additional technician is necessary to effect adjustments, or a physician effects adjustments who then must again undergo sterilization or risk contamination. Accordingly, there is a need for interchangeability of CCDs or other imagers (and the camera heads or other devices which contain them) with camera control units without sacrificing video display, and without the need for time-consuming control unit adjustments.
In addition to the lack of interchangeability, existing camera systems are generally incapable of collecting information to record uses of the camera system to provide a performance history. Such information may be useful for example, to determine when the camera system needs maintenance. Accordingly, there is also a need for a video camera system which may collect operating history information during the camera system's life so that this information may be later used by the system or operator. There is also a need for a camera system which provides these benefits but is relatively small and manipulable.